Process for preparing organometal compounds



United States Patent "ice 3,197,392 PRBCESS iRElARlNG QRGANQMETAL QQMhUUNBS Ernest F. Silversmith and Vialtsr John Sloan, Wilmington,

Bah, assignors to i. du Pont de Nemours and Company, Wilmington, DeL, a corporation or Delaware No Drawing. Filed Nov. 39, 1951, Ser. No. 156,128 29 Claims. (Cl. 2il459) This invention relates to a process for preparing organemetal compounds and particularly to an improved electrolytic process, especially for the manufacture of tetraallryl lead antiknock compounds.

Electrolytic syntheses of organometals are known. For

example, Tafel, Ben, 44, 327 (i911), obtained tetraisopropyl lead by electrolyzing an aquesous acid solution of acetone at a lead cathode in the absence of air. Such method, however, is not general and appears impractical for organolead production because of low yields and side reactions. Later (in 1925) Calingaert and Mead disclosed tetraalkyl lead formation at a lead cathode by electrolyzing a catholyte consisting of an alkyl halide in either alcoholic caustic (Calingaert in U. S. Patent 1,539,297) or aqueous caustic containing casein (Mead in U. S. Patent 1,567,159). They hypothesized: Apparently the hydrogen formed at the cathode reduces the reaction mass, forming lead di-ethyl, which is unstable at the temperature of the catholyte, and breaks up thermally into lead and lead tetraethyl. The above disclosure suggests that a potential source of hydrogen is necessary, such a the hydroxylic solvent employed, and further that, if diethyl lead is an intermediate, the yield based on lead can be no more than 50% of the consumed lead. In fact, under the disclosed conditions the tetraethyl lead yields tend to be low and the cathode deteriorates. Further, the ethylating agent tends readily to be destroyed in side reactions, by reaction for example with the caustic present, particularly in alcohol.

Besides the cathodic processes, anodic oxidations have also been employed to produce organometallics, as for example by Hein et al., Z. anorg. Allgem. Chem., 141, 161 (1924), who obtained tetraethyl lead by electrolyzing sodium zinc triethyl at a lead anode, and by Ziegler in British Patent 814,609 (1959) who discloses synthesis of Group ll-V metal alkyls by electrolyzing a complex aluminum alkyl at an anode composed of the Group ill-V meta-l. Numerous other references disclose similar processes. All such anodic processes are characterized by the fact that the source of the organic groups to begin with is invariably another organometal (often a complex of two or more such compounds), the net result of the electrolytic oxidation being replacement of metal in the starting material by metal of the anode. That the anodic process requires organometal starting material is an important disadvantage, for such materials normally are diliicult or costly to make and require special storage and handling under inert atmospheres.

An object of the invention is to provide an improved process for making hydrocarbon metal compounds electrolytically from relatively inexpensive and readily avail able starting materials. A particular object is to make hydrocarbon lead antiknock compounds by such process which avoids the use of organometal starting materials. Another object is to provide an improved method of alkylating lead electrolytically, wherein the current, electrode material and alkylating agent are more efficiently utilized, and whereby tetraalkyl lead antiknock compounds 3 ,1917 ,3 Patented July 27, 1965 are obtained in better yields than by heretofore suggested methods of electrolytic reduction. Other objects are to advance the art. Still other objects will appear hereinafter.

The above and other objects may be accomplished in accordance with this invention which comprises the process for preparing organometal compounds having hydrocarbon radicals bonded directly to a metal selected from the group consisting of lead, tin, arsenic, antimony and bismuth, which process comprises electrolyzing, at a cathode of the selected metal, a solution of an alkylating agent in a normally liquid, non-hydroxylic catholyte which, exclusive of the alkylating agent, has a higherreduction potential than the alkylating agent, employing at least 0.61 mole of alkylating agent per kilogram of solution, said alkylating agent being at least one member of the group consisting of (a) esters of the formula RX wherein X is an anion whose conjugate acid, I-lX, has a molecular weight greater than 20 and a pKa in water of less than about 6 and R is a hydrocarbon radical of 1 to 10 carbon atoms having a saturated carbon atom attached to X and (b) onium salts of the formula G QY wherein G Q is an onium cation in which Q is an element selected from groups VA and VIA of the Periodic Table, I1. is an integer of 3 to 4, G is a hydrocarbon radical at least one of which is R as defined above, and Y is salt-forming anion, which onium salts are weakly acidic to weakly basic, their water solutions having a pH between 5 and 10, and recovering the organometal compound from said solution.

In general the organometal compounds o obtained are well known to the art and are known to be useful for a wide variety of purposes. The lower hydrocarbon lead compounds are well known antiknock agents. The other organometal compounds are known to be useful as catalysts, as fungicides, as insecticides, as antiknock agents, and the like.

In general, the process comprises passing a direct elect tric current through a cathode of the metal to be alkylated, through a non-hydroxylic electrolyte containing an alkylating agent in contact with the cathode and then, to complete and repeat the circuit, to an anode and back to the cathode. The organometal compound is recovered from the catholyte by conventional means, the properties and handling characteristics of the organometal compounds being known. No special or unusual equipment or cell conditions are required. The process is easy and economical to operate and may be conducted at relatively low voltages and current densities and at ordinary ambient temperatures and pressures.

The apparatus employed for carrying out the process and the method of operating such apparatus may be any of those which are conventional for carrying out electrolytic processes. Suitable apparatus and methods are described by S. Swann, In, in the chapter beginning on page 385 of Technique of Organic Chemistry, A. Weissberger, editor, vol. II, 2nd ed. (1956), Interscience New York, N. Y. Preferably, the process is carried out in an electrolytic cell in which the catholyte is separated from the anolyte by a membrane which is permeable to an electric current, that is, in which the cell is divided into a catholyte compartment and an anolyte compartment by such a membrane. Suitable apparatus of this character is disclosed by S. Swann, In, above, by Calingaert in U. S. Patent 1,539,297, by Mead in U. S. Patent 1,567,159, and by Ziegler et al. in U. S. Patent 2,985,568. While the membrane may be omitted, optimum results are obtained when it is present. Usually, the membrane will be made of a porous substance which permits transport of ions from one solution to the other, i.e., an ion-permeable membrane. A variety of such membrane materials are known to the art and may be employed in the process of this invention, it being understood that such materials may differ considerably in their resistance. to the flow of electric current which will affect the selection of the particular material for a particular apparatus and condition of operation. Examples of suitable membrane materials are porous porcelain, asbestos, parchment, polyethylene, glass fiber paper, films and sheets of ion exchange resins and the like, all of which are available commercially. Usually, .it will be preferred to employ a cation-permeable membrane formed of a cation-ion exchange resin. The anode may be made of any desired electrode material chosen with regard to the composition of the anolyte with which it will be in contact. While the catholyte employed in the process of this invention must be non-hydroxylic, the anolyte may be either hydroxylic or non-hydroxylic, provided it has the required conductivity for the electric current. The cell may also be provided with means for heating, cooling, and agitating the electrolytes, for maintaining an inert atmosphere when desired, and for refluxing or maintaining superatmospheric pressures Where volatile materials are employed or produced, such means being conventional and well known to the art.

The alkylating agent, preferably, is an ester of the formula RX wherein X is an anion whose conjugate acid, l-IX, has a molecular weight greater than 20 and a pKa in water of less than about 6, most preferably less than 4, and R is a hydrocarbon radical of 1 to 10 carbon atoms having a saturated carbon atom attached to X. The hydrocarbon radical is usually acyclic and may be saturated or unsaturated, including ethylenically and acetylenically unsaturated, and may contain carbocyclic substituents, such as cycloaliphatic and aromatic groups. The chain length of the radical R does not appear to be critical for operability. Normally, however, it will have less than about 10 and preferably less than 6 carbon atoms. Usually, the most valuable metal compounds to be produced are those in which the organo radical is a primary alkyl radical, particularly of 1 to 2 carbon atoms, i.e., methyl or ethyl, and hence R most preferably will be such an alkyl radical. The anion X may be that of an inorganic acid or an organic acid. Thus, the RX esters include halides in which the halogen has an atomic number of at least 17, sulfates, sulfonates, phosphates, phosphonates, carboxylates, and the like. Preferably, the esters are the esters of non-oxidizing mineral acids, including sulfuric acid, and most preferably the halides.

Representative RX esters which are suitable for use in the process of the present invention are ethyl bromide, diethyl sulfate, ethyl iodide, ethyl chloride, ethyl acetate, dibutyl sulfate, methyl chloride, methyl iodide, methyl bromide, allyl chloride, benzyl bromide, n-butyl bromide, dimethyl sulfate, isopropyl bromide, isobutyl iodide, hexyl bromide, octyl bromide, cyclohexylmethyl bromide, crotyl chloride, 5-hexenyl iodide, 3-butenyl bromide, dipropyl sulfate, ethyl hexyl sulfate, butyl methanesulfonate, ethyl p-toluenesulfonate, benzyl diethyl phosphate, methyl benzoate, ethyl trifluoroacetate, and allyl propionate. Mixtures of any two or more of such alkylating agents may be employed if desired, including those wherein the radical R is different to produce mixtures of organometallic compounds and mixed organometallic compounds containing two or more different hydrocarbon radicals in the molecule.

Another, less preferred, group of alkylating agents are the onium salts of the formula G QY wherein G Q is an onium cation in which Q is an element selected from groups VA and VIA of the Periodic Table, n is an integer of 3 to 4, G is a hydrocarbon radical at least one of which is an alkylating hydrocarbon radical corresponding to R in the RX esters above defined, i.e., a hydrocarbon radical of l to carbon atoms having a saturated hydrocarbon radical attached to QY, and Y is a salt-forming anion,

which onium salts are weakly acidic to Weakly basic, that is, water solutions of such onium salts must have a pH between 5 and 10. Preferably, the anion Y corresponds to the anion X in the RX esters. The onium salts are well known compounds which are readily obtainable by the reaction of an RX ester with an alkylatable onium-forming amine, phosphine, arsine, thioether, or the like. They may be formed in situ in the non-hydroxylic catholyte solvent, thereby providing an alkylating, current-carrying catholyte. In solution in the catholyte, such onium salts may reform and be in equilibrium with the RX ester. For example, an acetonitrile solution, prepared by adding methyl diethyl sulfonium iodide or by separately adding methyl iodide and diethyl sulfide, will contain methyl diethyl sulfoniurn iodide in equilibrium with such species as methyl iodide, ethyl iodide, diethyl sulfide and methyl ethyl sulfide.

Representative onium salts which are suitable for use as alkylating agents in the process of the present invention include tetraethylammonium bromide triethylsulfonium bromide ethyltriphenylphosphonium bromide tetraethylammonium iodide methyldiethylsulfonium iodide tetrarnethylammonium bromide trimetnylsulfonium iodide tetraethylammonium diethyl phosphate tetrapropylammonium bromide tetraethylammonium ethyl sulfate tetrabutylphosphonium bromide tetrabenzylarsonium bromide dioctadecyldimethylarnmonium chloride benzyltriethylammonium propionate triethylsulfonium iodide triethylselenonium bromide allyltriethylammonium acetate ethyltriphenylphosphonium iodide, and tetra-n-amylammonium fluoride.

The RX esters are the more efiicient-alkylating agents, particularly as to the utilization of current, and usually result in higher yields of the desired compounds. Also, the RX esters are the more economical source of the alkylating agents since the onium salts are ordinarily prepared from them. However, the onium salts are current-carrier compounds and, when dissolved in a nonhydroxylic organic solvent, impart current-carrying characteristics to the solution. In preferred embodiments of the invention, an RX ester is used in combination with one or more of the onium salts, or with a catholyte-soluble current-carrying halide of a metal of groups IA or IIA of the Periodic Table. The alkylating radical in the onium salt may be the same or different from the radical R in the particular RX ester. In such combination, the onium salt or salts function primarily as the currentcarrier. Due to the greater reactivity of the RX esters, the organometal compound produced usually will contain the hydrocarbon radical from the RX ester predominantly, with little or none of the alkylating radical from the onium salts, even when the alkylating radical of the onium salt is different from the alkylating radical in the RX ester employed.

According to the process of thi invention, the catholyte must be non-hydroxylic, usually a solution of a nonhydroxylic current-carrying compound in a normally liquid non-hydroxylic organic solvent. However, it is not necessary to maintain rigorous anhydrous conditions and to completely exclude ordinary atmospheric component from the cell or the cathode. In other words, traces of water, such as those present in the atmosphere, are permissible. The catholyte must be normally liquid, i.e., liquid at normal room temperatures and pressures, and have .a reduction potential greater than that of the alkylating agent. In other words, the

5 catholyte should be substantially inert to the rest of the system, particularly to the organometal compounds being produced, and should not undergo reaction at the cathode in preference to the alkylating agent.

The non-hydroxylic organic solvents are substantially non-acidic, that is, they have a pKa of at least about 20, as determined by the method of Pearson and Dillon, JACS, 75, p. 2439 (1953). Suitable non-hydroxylic organic solvents are the organic amides, preferably of secondary amines, including carboxamides, sulfonamides, phosphoramides, and cyanamides; nitriles; sulfoxides; su fones; ethers; halohydrocarbons; thiocyanates; carboxylic esters; and ketones. Specifically, there may be used acetonitrile, propionitrile and higher homologs; N,N-dimethylformamide, N,N-dimethyl acetamide, N-methylcaprolactam, N-methylpyrrolidone, N,N-diethyl formamide; hexamethylphosphoramide, hexaethylphosphoramide; N,N-dimethylethanesulfonamide; dirnethyl sulfoxide and other lower alkyl sulfoxides such as diethyl sulfoXide;

acetone, methyl ethyl ketone and diethyl ketone; diethylene glycol dimethyl ether and diethylene glycol methyl ethyl ether; ethyl thiocyanate, propyl thiocyanate; propylene carbonate; N,N-dialkylamino nitriles such as N,N- dimethylcyanarnide and homologs. Mixtures of any two or more of such solvents may be used as the catholyte solvent. Where the alkylating agent is normally liquid and can be rendered sufficiently conductive of electric current, it can be used as the catholyte solvent.

The current-carrying compound, which may be dissolved in the catholyte solvent to render it electrically conductive and hence to form the catholyte of the present invention, may be varied widely. It need only be soluble in the non-hydroxylic organic solvent to the extent required to produce a catholyte having the required electric conductivity which in general should be at least about 0.0005 ohm cm. and, preferably, from 10 to 100 times this value. For example, the conductivity of a 10% wt. solution of tetraethylarnmonium bromide in acetonitrile i 0.027 ohrncm.- at 50 C. It is well known to the art to impart electrical conductivity to normally non-conductive organic liquids, including nonhydroxylic organic liquids, by means of current-carrying solutes. This practice and the materials employed are disclosed by S. Swann, In, hereinbefore referred to, and in the following literature:

(a) Harned and Owen, The Physical Chemistry of Electrolytic Solutions, 3rd ed, Reinhold, New York (1950).

(b) Fuoss and Accascina, Electrolytic Conductance, Interscience, New York, (1959).

Tables Annuelles de Constantes et Donnies Numeriques 18, Conductivity of Electrolytes, Hermann, Paris (1937).

(d) Audrieth and Kleinberg, Non-Aqueous Solvents (Applications as Media for Chemical Reactions), John Wiley and Sons, New York (1953).

In general, suitable inert current-carriers are dissolved inorganic or organic salts which are either neutral, weakly basic, or weakly acidic, i.e., show a pH between 5 and in water solution. They include univalent and polyvalent salts exemplified by onium, alkali metal, alkaline earth metal, and rare earth metal halides, perchlorates, thiocyanates, sulfonates, phosphonates, and carboxylates. In the process of the present invention, it will generally be preferred to employ one or more onium salts of the formula G QY wherein G is a hydrocarbon radical of 1 to 10 carbon atoms having a saturated carbon atom attached to QY, n is an integer of 3 to 4, Q is an element selected from the groups VA and VIA of the Periodic Table, preferably nitrogen or sulfur, and Y is a saltforming anion, which onium salts are Weakly acidic to weakly basic, or one or more catholyte-soluble currentcarrying halides of the metals of groups 1A. and HA of the Periodic Table, i.e., halides of the alkali metal and alkaline earth metals which are soluble in the catholyte solvent.

Representative current-carrying compounds which are suitable for use in the process of the present invention are lithium bromide, sodium iodide, potassium thiocyanate, lithium perchlorate, potassium iodide, calcium bromide, lanthanum chloride, lithium chloride, triphenylmethyl bromide, diphenyliodonium iodide, tetraethylarnmonium bromide, triethylsulionium bromide, triphenylethylphosphonium iodide, dioctadecyldimethylamrnonium chloride, methyldiethylsulfonium iodide, and the other onium salts which have been disclosed hereinbefore as alkylating agents. Combinations of any two or more of such current-carrying compounds may be used.

The alkylating agent, the solvent, and the currentcarrying salt are readily coordinated in a wide variety of combinations to provide suitable catholytes for the alkylation of the cathodic metals. In general, the non-hydroxylic solvent will be the major component of the cathoiyte. Th alkylating agent will be present in the proportion of at least 0.01 mole per kilogram (1,000 grams) of the total catholyte, i.e., the total of catholyte solvent, currenhcarrier and alkylating agent, usually from about 0.01 to about 8.7 moles, and most preferably from about 0.25 to about 5 moles. When an RX ester is used in combination with an onium salt, the RX ester will usually be present in a concentration of from about 0.1 to about 8.7 moles per kilogram of solution, preferably at least about 0.4 mole, and most preferably at least about 1 mole. The upper limit of the alkylating agent will vary, depending on its molecular wei ht and its solubility in the non-hydroxylic organic solvent. The current-carrying compound may be employed in the proportion of from 0.001 to about 2 moles per kilogram of catholyte, usually from about 0.01 to about 0.5 mole, and preferably from about 0.05 to about 0.5 mole. The upper limit of the current-carrier will further depend upon its solubility in the total catholyte composition.

The electrolysis is accomplished by passing a direct current across the cell, that is, through the cathode, the catholyte, the anolyte, and the anode. The voltage applied across the cell is not critical so long as it is sufiicient to overcome the resistance of the cell, including that of the catholyte and the anolyte, and to establish current flow through the cell. The minimum voltage depends upon such factors as cell design, the particular catholyte, particularly the particular current-carrying com pound and the concentration thereof in the catholyte solvent, the choice of alkylating agent. At least sulficient volts are required to reduce the alkylating agent at the cathode and to overcome the various resistances in the cell. In general, the reduction of the alkylating agent appears to require about 1 to 2 volts and, in the particular systems explored, the minimum total voltage required usually was of the order of 4 to 5 volts. It is seldom necessary to exceed about 15 volts in ordinary equipment and most catholytes, but higher voltages up to about 30 volts have been used. Much higher voltages can be employed if desired. The usual operating range is from about 4 to about 15 volts. The current density may range from 0.0001 amp/sq. cm. to about 1 amp/sq. cm. of cathode area, but preferably is kept below about 0.5 amp/ sq. cm. The lower limit of current density will usually be dictated by the desired rate of production of the organo-.

metal compound under the existing conditions. Usually, the current density will be from about 0.1 to about 0.4 amp/sq. cm.

Usually, the process, i.e., the electrolysis in the cell, will be car ied out at normal room temperatures and pressures. However, the operating temperatures may be higher or lower, consonant with a practical rate of production of the organometal compound and the thermal stability of the system. While temperatures of from about 20 C. to C. are preferred, temperatures as low as 0 C. and as high as C. may be used. The

pressure on the system should be at least sulficient to maintain a liquid catholyte, and otherwise may be above or below atmospheric pressures. Reflux may be used in the usual way to retain volatile components in the cell and to aid in controlling reaction conditions. Also, where the materials employed or the organometal compounds produced are sensitive to atmospheric moisture or oxygen, an inert atmosphere such as nitrogen may be employed.

In the examples presented hereinafter, the process is carried out as a batch operation. However, the process is adaptable to continuous operation. The reaction times may be considerably less than those shown in tr e examples and, particularly in the tetraalkyl lead system, the tetraalkyl lead begins to appear in the catholyte almost immediately after the electrolysis is started and, While the conversion at short times is low, the yields are high, of the order of 90% or better on both current and lead. Thus, in the continuous process, the catholyte containing the product may be continuously removed, treated for recovery of the organometal product, and recycled and replaced in whole or in part by fresh catholyte.

In order to more clearly illustrate this invention, preferred modes of practicing it, and the advantageous results to be obtained thereby, the following examples are given in which the quantities are in parts by weight unless specifically indicated otherwise.

Example 1 A. An electrolytic cell is used which comprises a lead cathode, a platinum anode, and, separate catholyte and anolyte compartments separated by a cation-permeable membrane (a commercial product which is understood to be a sulfonic acid type cation-ion exchange resin). The catholyte solution consists of 29 parts of ethyl bromide (EtBr), 5 parts of tetraethyl-ammonium bromide (Et NBr) and 175 parts of acetonitrile (corresponding to 1.273 moles of EtBr and 0.114 mole EQNBr per kilogram of solution). The anolyte is 28 parts of sodium carbonate in 250 parts water. With the electrolytes at room temperature, the direct current is turned on and, over a minute period, the voltage is increased gradually -from about 6 to about 15 volts and the current from about 0.2 to about 11.5.amperes, corresponding to a final current density of about 0.02-0.03 amp/sq. crn. These conditions are continued for about 4- hours, during which time the temperature rises to about C. The catholyte is removed, decanted from a trace of insoluble matter, thoroughly mixed with 800 parts water and 150 parts pentane, and the resulting two-layer system separated. Another 150 parts pentane is used to reextract the aqueous layer, and the total pentane extract is distilled under reduced pressure to obtain tetraethyl lead in yield based on the current passed and based on the weight lost by the cathode during the electrolysis.

Alternatively the electrolyzed catholyte composition may be tractionally distilled or steam distilled to give tetraethyl lead.

B. Similarly in the above electrolytic procedure, but with the anolyte a solution of 5 parts of tetraethyl-ammoniurn bromide in 175 parts of acetonitrile, the yield of tetraethyl lead is 77% based on current and 81% based on lead. During this latter procedure, bromide is oxidized at the anode; the oxidation product is present in the anolyte as polybromide ions, e.g., B13, from which molecu:lar bromine may be recovered by known methods. If desired, a scavenger for oxidant bromine may be added to the starting anolyte. For example, the scavenger may be an olefin (e.g., ethylene or cyclohexane) to form the olefin dibromide, or it may be a strong base anion exchange resin in the halide form, such resins being known in the art to chemisorb bromine as polybromohalide ions.

C. Other current-carriers can replace tetraethyl-ammonium bromide in the catholyte. Typical examples,

8 with results obtained by the procedure of Example 1A,

are:

Tetraethyl Lead Yield, Current-Carrier Mole/kg. Percent Catholyte Based on Lead Lithium bromide 0. 524 Triethylsulfomum bromide. 0. 121 81 Sodium iodide 0. 159 76 Potassium thio 0. 243 100 Lithium perchlorate 0. 100 Potassium iodide 0. 84 Triphenylethylpno 0. 091 86 alclum bromide 0. 012 100 Triphenylmethyl bromide 0. 094 72 It should be noted that triphenylrnethyl bromide, normally a covalent, i.e., non-dissociated molecule, apparently dissociates into current-carrying ions in acetonitrile under the conditions employed. Thus, the current-carrier need not be a preformed salt existing as ions in the solid state, but need only be capable of rendering the solution electrically conducting.

Example 2 The procedure of Example 1A is followed except that acetonitrile is replaced by an equal volume of a non-hydroxylic solvent listed below, the moles of ethyl bromide (EtBr) and of tetraethylammonium bromide (Et NBr) per kilogram of catholyte varying in accord with the variations in the density of the solvents, as shown.

Moles/kg. eatholyte Tctraethyl Lead Yield,

Solvent Percent EtBr EmN'Br Based on Lead N, N-Dimethyliormamida. 1. 077 0. 007 46 Dimethyl sulfoxideu 0. 943 0. 085 16 1, .Z-Dirnethoxyethan 1.107 0. 105 47 Methylene chlorido O. 794 0. 071 71 Propylene carbonate 0. 869 0.078 40 Ethyl thiooyauate 1. 031 0. 003 84 N, N-Dimcthylcyanami e 1. 142 0. 102 44 Tetracthyl I Moles/kg. Lead Yield,

Ethylaung Agent Catholytc Percent Based on Lead Dicthyl sulfate 0.81 81 Ethyl iodide 4. 24 72 Ethyl chloride. 1. 51 93 Ethyl acetate--. 1. 40 10 Tetrocthylammonium bromide. 0.13 (total) 12 'lriethylsuliouium bromide 1 0. 14 33 1 N0 tetracthylarmnonium bromide added.

The last two agents, onium salts, are also currentcarriers (Example 1). Thus, in the method of the inventron, the same substance may provide alkylating radicals and current-carrying ions. While the RX esters themselves do not ordinarily con uct the current, they may be used to produce current-carrying oniurn salts in situ in the catholyte solvent, for example, by reacting an alkylating agent such as ethyl iodide with a suitable onium-formsome of the methyl iodide to yield trimethylsulfonium iodide as the current-carrier.

YIELDS OF TETRAMETHYL LEAD, PERCENT Method A ing base such as triethylamine to form tetraethylammonium iodide or such as diethyl sulfide to form triethyl sulfonium iodide.

Example 4 vention, applied to the preparation of tetraethyl lead, gs/herein the catholyte solvent is a non-hydroxylic substantially inert organic solvent. in comparison, when the above procedure Was used, employing an alkylating agent such as ethyl bromide in a catholyte consisting also of ethanolic sodium hydroxide (as suggested by Calingaert in US. Fatent 1,539,297), the yield of tetraethyl lead was practically nil. With aqueous sodium hy roxide containing ethyl iodide emulsified therein with casein (as described by Mead in US. Patent 1,567,159), yields of tetraethyl lead of up to based on current and up to 33% based on lead may be obtained. The above Examples 1 and 3, utilizing ethyl halides in the acetonitrileyte, provides tetraethyl lead in significantly greater yield, on the order of Til-100% based on current and lead.

Example 5 A catholyte consisting of 200 ml. acetonitrile, 2 ml. methyl chloride (MeCl), and 15 g. tetraethylammonium romide (EtJJBr), corresponding 0.23 mole MeCl and .41 mole Et NBr per kg. of catholyte, is electrolyzed by he method of Example 1B (i.e., the anolyte consists of 5 g. tetraethylammonium bromide in 200 ml. acetonitrile). Voltage and current are raised over a period of about 15 minutes to about 15 volts and 1-1.5 amperes, corresponding to a current density of about 0.02-0.03 amp/sq. cm. A ter 4 hours, the catholyte is decanted from a trace of sludge and analyzed. The tetraallryl lead content, calculated as tetramethyl lead (probably the predominant product), corresponds to a 93% yield based on lead consumed and 75 based on current.

Satisfactory results are also obtained in the above procedure, on utilizing methyl iodide or methyl bromide. Likewise, mixtures of methylating and ethylatingesters may be employed, e.g., methyl chloride and ethyl bromide, to produce mixtures of tetramethyl lead and tetraethyl lead, along with mixed tetraalkyl lead wherein methyl and ethyl groups are present in the same molecule.

There may also be employed, as both allrylating agent and a current-carrier, methyl diethylsulfonium iodide which is readily prepared in situ in acetonitrile by mixing methyl iodide with diethyl sulfide, whereby mixtures of methyl and ethyl lead compounds are produced.

Example 6 A. The method of Example 1A is followed. The catholyte consists of 171 g. acetonitrile (225 ml.)

5 g. (Cranmer (0.15 mole/kg. catholyte) 45.5 g. C3 1 (1.44 mole/kg. catholyte) The anolyte is Na CO in water as given.

B. Procedure A above is repeated except that 2.54 g. (3 ml.) of dimethyl sulfide replaces the tetramethylammonium bromide current-carrier, a iarentl reactin with Based on lead Based on curr Example 7 In the apparatus of Example 1 are placed a catholyte consisting of 250 ml. N,N-dimethylformamide, 22 ml. allyl chloride and 5.5 g. lithium chloride (corresponding to 1.03 moles of allyl chloride and 0.50 mole of lithium chloride per kg. of catholyte), and an anolyte solution of 23 g. sodium carbonate in 250 ml. Water. Electrolysis is carried out for 4.5 hours at a current density of 0.012 amp/sq. cm. and a temperature or" about 30 C. thoughout the run. The organolead content of the catholyte corresponds to a 65% yield based on lead and calculated as tetraalkyl lead.

. Example 8 Example 1A is repeated With an arsenic cathode and a catholyte solution of 5 g. tetraethylammonium bromide and 10 ml. benzyl bromide in 200 ml. acetonitrile, corre sponding to 0.48 mole of benzyl bromide and 0.14 mole of Et NBr per kg. of catholyte. The electrolysis is conducted under a nitrogen atmosphere for about 4 hours at 3-9 volts, 0.05-05 ampere (current density=0.0010.01 amp/sq. cm), and 2535 C. The resulting catholyte is concentrated to a small volume at reduced pressure, and the residue Washed With Water and then ethyl ether to give tetrabenzylarsonium bromide in a yield of about 9% based on the arsenic. This product apparently results from the reaction of benzyl bromide with the tribenzyl arsenic product of the electrolysis.

When cathodes of bismuth and antimony are employed in the above procedure, they are similarly observed to dissolve during electrolysis. From the catholytes organobismuth and organoantimony derivatives may be obtained.

Eicample 9 Example 1A is repeated with a cathode of tin instead of lead, to form tetraethyl tin in a yield of about 72% based on the tin, determined by bromide titration of the product.

Similarly other alkylating agents may be employed, for example n-butyl bromide to produce tetra-n-butyl tin.

It Will be apparent from the preceding examples that the method of this invention, wherein reductive alkylation is effected in a non-hydroxylic catholyte, is applicable to the production of organo derivatives of metals of groups IVA and VA of the Periodic Table, the organo derivatives being those wherein at least one hydrocarbon radical is directly attached through a saturated carbon atom to said metal.

it will be understood that the preceding examples have been given for illustrative purposes solely, and that this invention is not limited to the specific embodiments de scribed therein. On the other hand, it will be readily apparent to those skilled in the art that, subject to the limitations set forth in the general description, many variations can be made in the materials, proportions, con- It employs relatively cheap and readily available- 1 l in other processes for making such organometal compounds, such as the alkyllead compounds. Accordingly, it will be apparent that this invention constitutes a valuable advance in and contribution to the art.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. The process for preparing organometal compounds having hydrocarbon radicals bonded directly to a metal selected from the group consisting of lead, tin, arsenic, antimony and bismuth, which comprises electrolyzing, at a cathode of the selected metal, a solution of an alkylating agent in a normally liquid, initially non-hydroxylic catholyte which, exclusive of the alkylating agent, has a higher reduction potential than the alkylating agent employing at least 0.01 mole of alkylating agent per kilogram of solution, said alkylating agent being at least one member of the group consisting of (a) esters of the formula RX wherein X is an anion whose conjugate acid, HX, has a molecular weight greater than 20 and a pKa in water of less than about 6 and R is a hydrocarbon radical of 1 to 10 carbon atoms having a saturated carbon atom attached to X and (b) onium salts of the formula G QY wherein G Q is an onium cation in which Q is an element selected from groups VA and VIA of the Periodic Table, 12 is an integer of 3 to 4, G is a hydrocarbon radical at least one of which is R as defined above, and Y is salt-forming anion, which onium salts are weakly acidic to weakly basic, their Water solutions having a pH between 5 and 10, said catholyte containing a current-carrier in an amount sufiicient to provide a conductivity of at least 0.0005 ohm" crnf said current-carrier being a dissolved current-carrying salt which, in water, has a pH in the range of 5 to and recovering an organometal compound from said solution.

2. The process for preparing organometal compounds having hydrocarbon radicals bonded. directly to a metal selected from the group consisting of lead, tin, arsenic, antimony and bismuth, which comprises electrolyzing, at a cathode of the selected metal, a solution of an alkylating agent in a normally liquid, initially non-hydroxylic catholyte which, exclusive of the alkylating agent, has a higher reduction potential than the alkylating agent, employing from about 0.01 to about 8.7 moles of alkylating agent per kilogram of solution, said alkylating agent being at least one ester of the formula RX wherein X is an anion whose conjugate acid, HX, has a molecular weight greater than 20 and a pKa in water of less than about 6 and R is a hydrocarbon radical of 1 to 10 carbon atomshaving a saturated carbon atom attached to X, said catholyte containing a current-carrier in an amount sufiicient to provide a conductivity of at least 0.0005 ohm cmf said currentcarrier being a dissolved current-carrying salt which, in water, has a pH in the range of 5 to 10; and recovering an organometal compound from said solution.

3. The process for preparing organometal compounds having hydrocarbon radicals bonded directly to a metal selected from the group consisting of lead, tin, arsenic, antimony and bismuth, which comprises electrolyzing, .at a cathode of the selected metal in an electrolytic cell in which the catholyte is separated irom the anolyte by a membrane permeable to an electric current, a solution of an alkylating agent in a normally liquid, initially non-hydroxylic catholyte which, exclusive of the alkylating agent, has a higher reduction potential than the alkylating agent, employing from about 0.01 to about 8.7 moles of alkylating agent per kilogram of solution, said alkylating agent being at least one member of the group consisting of (a) esters of the formula RX wherein X is an anion whose conjugate acid, HX, has a molecular weight greater than 20 and a pKa in water of less than about 6 and R is a hydrocarbon radical of 1 to 10 carbon atoms having a saturated carbon atom attached to X and (b) onium salts of the formula G QY wherein G Q is an onium cation in which Q is an element selected from groups VA and VIA of the Periodic Table, I: is an integer of 3 to 4, G is a hydrocarbon radical at least one of which is R as defined above, and Y is a salt-forming anion, which onium salts are weakly acidic to weakly basic, their water solutions having a pH between 5 and 10, said catholyte containing a current-carrier in an amount sufiicient to provide a conductivity of at least 0.0005 ohm cmf said currentcarrier being a dissolved current-carrying salt which, in water, has a pH in the range of 5 to 10; and recovering an organometal compound from said solution.

4-. The process for preparing organometal compounds having hydrocarbon radicals bonded directly to a metal selected from the class consisting of lead, tin, arsenic, antimony and bismuth, which comprises electrolyzing, at a cathode of the selected metal in an electrolytic cell in which the catholyte is separated from the anolyte by an ion-permeable membrane, a solution of an alkylating agent in a normally liquid, initially non-hydroxylic catholyte which, exclusive of the alkylating agent, has a higher reduction potential than the alkylating agent, employing from about 0.01 to about 8.7 moles of alkylating agent per kilogram of solution, said alkylating agent being at least one ester. of the formula RX wherein X is an anion whose conjugate acid, HX, has a molecular weight greater than 20 and a pKa in water of less than about 6 and R is a hydrocarbon radical of 1 to 10 carbon atoms having a saturated carbon atom attached to X, said catholyte containing a current-carrier in an amount sufiicient to provide a conductivity of at least 0.0005 ohm Cl'l'l. said currentcarrier being a dissolved current-carrying salt which, in water, has a pH in the range of 5 to 10; and recovering an organometal compound from said solution.

5. The process for preparing organolead compounds having hydrocarbon radicals bonded directly to lead, which comprises electrolyzing, at a lead cathode in an electrolytic cell in which the catholyte is separated from the anolyte by an ion-permeable membrane, a solution of an alkylating agent in a normally liquid, initially non-hydroxylic catholyte which, exclusive of the alkylating agent, has a higher reduction potential than the alkylating agent, employing from about 0.01 to about 8.7 moles of alkylating agent per kilogram of solution, said alkylating agent being at least one member of the group consisting of (a) esters of the formula RX wherein X is an anion whose conjugate acid, HX, has a molecular weight greater than 20 and a pKa in water of less than about 6 and R is a hydrocarbon radical of 1 to 10 carbon atoms having a saturated carbon atom attached to X and (h) onium salts of the formula G QY wherein G Q is an onium cation in which Q is an element selected from groups VA and VIA of the Periodic Table, I1 is an integer of 3 to 4, G is a hydrocarbon radical at least one of which is R is defined above, and Y is a salt-forming anion, which onium salts are weakly acidic to weakly basic, their water solutions having a pH betwen 5 and 10, said catholyte containing a current-carrier in an amount sufficient to provide a conductivity of at least 0.0005 ohmcm.- said current-carrier being a dissolved current-carrying salt which, in water, has a pH in the range of 5 to 10 and recovering an organolead compound from said solution.

6. The process for preparing organolead compounds having h 'drocarbon radicals bonded directly to lead, which comprises electrolyzing, at a lead cathode in an electrolytic cell in which the catholyte is separated from the anolyte by an ion-permeable membrane, a solution of an alkylating agent in a normally liquid, initially non-hydroxylic catholyte which, exclusive of the alkylating agent, has a higher reduction potential than the alkylating agent, employing from about 0.01 to about 8.7 moles of alkylating agent per kilogram of solution, said alkylating agent being at least one ester of the formula RX wherein X is an anion whose conjugate acid, HX, has a molecular weight greater than 20 and a pKa in water of less than about 6 and R is a hydrocarbon radical of 1 to 10 carbon atoms having a saturated carbon atom attached to X, said catholyte containing a current-carrier in an amount suflicient to provide a conductivity of at least 0.0005 hmcmf said current-carrier being a dissolved current-carrying salt which, in water, has a pH in the range of to and recovering an organolead compound from said solution.

7. The process for preparing organolead compounds having hydrocarbon radicals bonded directly to lead, which comprises electrolyzing, at a lead cathode in an electrolytic cell in which the catholyte is separated from the anolyte by an ion-permeable membrane, a solution of an alkylating agent in a normally liquid, initially nonhydroxylic catholyte which, exclusive of the alkylating agent, has a higher reduction potential than the alkylating agent, employing from about 0.01 to about 8.7 moles of alkylating agent per kilogram of solution, said alkylat ing agent being at least one ester of the formula RX'wherein X is a halogen atom having an atomic number of at least 17 and R is a hydrocarbon radical of 1 to 5 carbon atoms having a saturated carbon atom attached to X, said catholyte containing a current-carrier in an amount sufficient to provide a conductivity of at least 0.0005 ohm- GEL-1, said current-carrier being a dissolved current-carrying salt which, in water, has a pH in the range of 5 to 10; and

recovering an organolead compound from said solution.

8. The process for preparing organolead compounds having hydrocarbon radicals bonded directly to lead, which comprises electrolyzing, at a lead cathode in an electrolytic cell in which the catholyte is separated from the anolyte by an ion-permeable membrane, a solution of an alkylating agent in a normally liquid, initially non-hydroxylic catholyte which, exclusive of the alkylating agent, has a higher reduction potential than the alkylating agent, employing from about 0.01 to about 8.7 moles of allrylating agent per kilogram of solution, said alkylating agent being at least one ester of the formula RX wherein X is a halogen atom having an atomic number of at least 17 and R is an alkyl radical of 1 to 2 carbon atoms, said catholyte containing a current-carrier in an amount sufiicient to pro- A vide a conductivity of at least 0.0005 ohm cm. said current-carrier being a dissolved current-carrying salt which, in water, has a pH in the range of 5 to 10; and recovering an organolead compound from said solution.

9. The process for preparing tetraethyl lead which comprises electrolyzing, at a lead cathode in an electrolytic cell in which the catholyte is separated from the anoiyte by an ion-permeable membrane, a solution of an ethyl halide in which the halogen has an atomic number of at least 17 in a normally liquid, initially non-hydroxylic catholyte which, exclusive of the ethyl halide, has a higher reduction potential thanthe ethyl halide, employing from about 0.01 to about 8.7 moles of ethyl halide per kilogram of solution, said catholyte containing a current-carrier in an amount sufficient to provide a conductivity of at least 0.0005 ohrrr cmf said current-carrier being a dissolved current-carrying salt which, in water, has a pH in the range of 5 to 10; and recovering tetraethyl lead from said solution.

The process for preparing tetramethyl lead which comprises electrolyzing, at a lead cathode in an electrolytic cell in which the catholyte is separated from the anolyte by an ion-permeable membrane, a solution of a methyl halide in which the halogen has an atomic number of at least 17 in a normally liquid, initially non-hydroxylic catholyte which, exclusive of the methyl halide, has a higher reduction potential than the methyl halide, employing from about 0.01 to about 8.7 moles of methyl halide per kilogram of solution, said catholyte containing a current-carrier in an amount sufficient to provide a conductivity of at least 0.0005 ohmcm. said current-carrier being a dissolved current-carrying salt which, in water, has a pH in the range of 5 to 10; and recovering tetramethyl lead from said solution.

11. The process for preparing an organolead compound in an electrolytic cell in which the catholyte is separated from the anolyte by an ion-permeable membrane, which comprises immersing a lead cathode in a non-hydroxylic catholyte in the cell, which catholyte consists essentially of a solution of (a) at least one ester of the formula RX wherein X is an anion whose conjugate acid, HX, has a molecular weight greater than 20 and a pK-a of less than about 6 and R is a hydrocarbon radical of 1 to 10 carbon atoms having a saturated carbon atom attached to X, and (b) an onium salt of the formula G QY wherein G is a hydrocarbon radical of l to 10 carbon atoms having a saturated carbon atom attached to QY, n is an integer of 3 to 4, Q is an element selected from groups VA and VIA of the Periodic Table, and Y is a salt-forming anion, which onium salts are weakly acidic to weakly basic, their water solutions having a pH between 5 and 10, in a normally liquid, non-hydroxylic organic solvent which has a higher reduction potential than said ester, in the proportions of from about 0.1 to about 8.7 moles of said ester and from about 0.07 to about 0.5 mole of said onium salt per kilogram of catholyte, and passing an electric current of from about 4 to about 30 volts and of a, current density or from about 0.01 to about 1 amp/sq. cm. through said cathode and said catholyte, and recovering an organolead compound from the catholyte.

12. The process for preparing tetraaliryl lead compounds in an electrolytic cell in which the catholyte is separated from the anolyte by an ion-permeable membrane, which comprises immersing a lead cathode in a non-hydroxylic catholyte in the cell, which catholyte consists essentially of a solution of (a) at least one alkyl halide of 1 to 5 carbon atoms in which the halogen has an atomic number of at least 17 and (b) an onium salt of the formula R NX wherein R is an alkyl radical of 1 to 10 carbon atoms and X is a halogen atom, in a normally liquid, nonhydroxylic organic solvent which has a higher reduction potential than the alkyl halide, in the proportions of from about 0.1 to about 8.7 moles of alkyl halide and from about 0.07 to about 0.5 mole of said onium salt per kilogram of catholyte, and passing an electric current of from about 4 to about 30 volts and of a current density of from about 0.01 to about 1 amp/sq. cm. through said cathode and said catholyte, and recovering at least one tetraalkyl lead from the catholyte.

13. The process for preparing tetraalhyl lead compounds in an electrolytic cell in which the catholyte is separated from the anolyte by an ion-permeable membrane, which comprises immersing a lead cathode in a non-hydroxylic catholyte in the cell, which catholyte consists essentially of a solution of (a) at least one alkyl halide of 1 to 2 carbon atoms in which the halogen has an atomic number of at least 17 and (b) an onium salt of the formula R NX wherein R is an alkyl radical of 1 to 10 carbon atoms and X is a halogen atom having an atomic number of at least 17, in a normally liquid, non-hydroxylic organic solvent which has a higher reduction potential than the alkyl halide, in proportions of from about 0.1 to about 8.7 moles of alkyl halide and from about 0.07 to about 0.5 mole of said onium salt per kilogram of catholyte, and passing an electric current of from about 4 to about 30 volts and of a current density of from about 0.01 to about 1 amp/sq. cm. through said cathode and said catholyte, and recovering at least one tetraalkyl lead from the catholyte.

14. The process for preparing tetraethyl lead in an electrolytic cell in which the catholyte is separated from the anolyte by an ion-permeable membrane, which comprises immersing a lead cathode in a non-hydroxylic catholyte in the cell, which catholyte consists essentially of a solution of (a) an ethyl halide in which the halogen has an atomic number of at least 17 and (b) an onium salt of the formula R NX wherein R is an ethyl radical and X is a halogen atom having an atomic number of at least 17, in a normally liquid, non-hydrcxylic organic solvent which has a higher reduction potential than the ethyl halide, in

the proportions of from about 0.1 to about 8.7 moles of ethyl halide and from about 0.07 to about 0.5 mole of said onium salt per kilogram of catholyte, and passing an electric current of from about 4 to about 30 volts and of a current density of from about 0.01 to about 1 amp/sq. cm. through said cathode and said catholyte, and recovering tetraethyl lead from the catholyte.

15. The process for preparing tetraethyl lead in an electrolytic cell in which the catholyte is separated from the anolyte by an ion-permeable membrane, which comprises immersing a lead cathode in a non-hydroxylic catholyte in the cell, which catholyte consists essentially of a solution of (a) ethyl bromide and (b) tetraethylammonium bromide in acetonitrile in the proportions of from about 1 to about 8.7 moles of ethyl bromide and from about 0.1 to about 0.5 mole of tetraethylammonium bromide per kilogram of catholyte, and passing an electric current of from about 6 to about 15 volts and of a current density of from about 0.02 to about 0.03 amp/sq. cm. through said cathode and said catholyte, and recovering tetraethyl lead from the catholyte.

16. The process for preparing tetraalkyl lead compounds in an electrolytic cell in which the catholyte is separated from the anolyte by an ion-permeable membrane, which comprises immersing a lead cathode in a non-hydroxylic catholyte in the cell, which catholyte consists essentially of a solution of (a) at least one alkyl halide of 1 to 2 carbon atoms in which the halogen has an atomic number of at least 17 and (b) an onium salt of the formula R SX wherein R is an alkyl radical of 1 to 10 carbon atoms and X is a halogen atom having an atomic number of at least 17, in a normally liquid, non-hydroxylic organic solvent which has a higher reduction potential than the alkyl halide, in proportions of from about 0.1 to about 8.7 moles of alkyl halide and from about 0.07 to about 0.5 mole of said onium salt per kilogram of catholyte, and passing an electric current of from about 4 to about 30 volts and of a current density of from about 0.01 to about 1 amp/sq. cm. through said cathode and said catholyte, and recovering at least one tetraalkyl lead from the catholyte.

17. The process for preparing tetraethyl lead in an electrolytic cell in which the catholyte is separated from the anolyte by an ion-permeable membrane, which comprises immersing a lead cathode in a non-hydroxylic catholyte in the cell, which catholyte consists essentially of a solution of (a) an ethyl halide in which the halogen has an atomic number of at least 17 and (b) an onium salt of the formula R SX wherein R is an ethyl radical and X is a halogen atom having an atomic number of at least 17, in a normally liquid, non-hydroxylic organic solvent which has a higher reduction potential than the ethyl halide, in the proportions of from about 0.1 to about 8.7 moles of ethyl halide and from about 0.07 to about 0.5 mole of said onium salt per kilogram of catholyte, and passing an electric current of from about 4 to about 30 volts and of a current density of from about 0.01 to about 1 amp/sq. cm. through said cathode and said catholyte, and recovering tetraethyl lead from the catholyte.

18. The process for preparing tetramethyl lead in an electrolytic cell in which the catholyte is separated from the anolyte by an ion-permeable membrane, which comprises immersing a lead cathode in a nonhydroxylic catholyte in the cell, which catholyte consists essentially of a solution of (a) a methyl halide in which the halogen has an atomic number of at least 17 and (b) an onium salt of the formula R NX wherein R is an alkyl radical of l to 2 carbon atoms and X is a halogen atom having an atomic number of at least 17, in a normally liquid, non-hydroxylic organic solvent which has a higher reduction potential than the methyl halide, in the proportions of from about 0.1 to about 8.7 moles of methyl halide and from about 0.07 to about 0.5 mole of said onium salt per kilogram of catholyte, and passing an electric current of from about 4 to about 30 volts and of a current density of from about 0.01 to about 1 amp/sq. cm. through said cathode and said catholyte, and recovering tetramethyl lead from the catholyte.

19. The process for preparing an organolead compound in an electrolytic cell in which the catholyte is separated from the anolyte by an ion-permeable membrane, which comprises immersing a lead cathode in a non-hydroxylic catholyte in the cell, which catholyte consists essentially of a solution of (a) at least one ester of the formula RX wherein X is an anion whose conjugate acid, HX, has a molecular weight greater than 20 and a pKa of less than about 6 and R is a hydrocarbon radical of l to 10 carbon atoms having a saturated carbon atom attached to X, and

(b) a current-carrying dissolved salt which, in water, has a pH in the range of 5 to 10, in a normally liquid, nonhydroxylic organic solvent which has a higher reduction potential than said ester, in the proportions of from about 0.1 to about 8.7 moles of said ester and from about 0.07 to about 0.5 mole of said salt per kilogram of catholyte, and passing an electric current of from about 4 to about 30 volts and of a current density of from about 0.01 to about 1 amp./ sq. cm. through said cathode and said catholyte, and recovering an organolead compound from the catholyte.

20. The process for preparing an organolead compound in an electrolytic cell in which the catholyte is separated from the anolyte by an ion-permeable membrane, which comprises immersing a lead cathode in a non-hydroxylic catholyte in the cell, which catholyte consists essentially of a solution of (a) at least one ester of the formula RX wherein X is an anion whose conjugate acid, HX, has a molecular weight greater than 20 and a pKa of less than about 6 and R is a hydrocarbon radical of 1 to 10 carbon atoms having a saturated carbon atom attached to X, and (b) a catholyte-soluble current-carrying halide of a metal of the group consisting of metals of groups IA and HA of the Periodic Table, in a normally liquid, non-hydroxylic organic solvent which has a higher reduction potential than said ester, in the proportions of from about 0.1 to about 8.7 moles of said ester and from about 0.07 to about 0.5 mole of said metal halide per kilogram of catholyte, and passing an electric current of from about 4 to about 30 volts and of a current density of from about 0.01 to about 1 amp/sq. cm. through said cathode and said catholyte, and recovering an organolead compound from the catholyte.

References Cited by the Examiner UNITED STATES PATENTS 1,5 39,297 5/25 Calingaert 2045 9 3,007,857 11/61 Braithwaite 204--59 3,007,858 11/ 61 Braithwaite 204-59 FOREIGN PATENTS 531,827 10/56 Canada.

" WINSTON A. DOUGLAS, Primary Examiner.

JOHN R. SPECK, JOHN H. MACK, Examiners. 

1. THE PROCESS FOR PREPARING ORGANOMETAL COMPOUNDS HAVING HYDROCARBON RADICALS BONDED DIRECTLY TO A METAL SELECTED FROM THE GROUP CONSISTING OF LEAD, TIN, ARSENIC, ANTIMONY AND BISMUTH, WHICH COMPRISES ELECTROLYZING, AT A CATHODE OF THE SELECTED METAL, A SOLUTION OF AN ALKYLATING AGENT IN A NORMALLY LIQUID, INITIALLY NON-HYDROXYLIC CATHOLYTE WHICH, EXCLUSIVE OF THE ALKYLATING AGENT, HAS A HIGHER REDUCTION POTENTIAL THAN THE ALKYLATING AGENT EMPLOYING AT LEAST 0.01 MOLE OF ALKYLATING AGENT PER KILOGRAM OF SOLUTION, SAID ALKYLATING AGENT BEING AT LEAST ONE MEMBER OF THE GROUP CONSISTING OF (A) ESTERS OF THE FORMULA RX WHEREIN X IS AN ANION WHOSE CONJUGATE ACID, HX, HAS A MOLECULAR WEIGHT GREATER THAN 20 AND A PKA IN WATER OF LESS THAN ABOUT 6 AND R IS A HYDROCARBON RADICAL OF 1 TO 10 CARBON ATOMS HAVING A SATURATED CARBON ATOM ATTACHED TO X AND (B) ONIUM SALTS OF THE FORMULA GNQY WHEREIN GNQ IS AN ONIUM CATION IN WHICH Q IS AN ELEMENT SELECTED FROM GROUPS VA AND VIA OF THE PREIODIC TABLE, N IS AN INTEGER OF 3 TO 4, G IS A HYDROCARBON RADICAL AT LEAST ONE OF WHICH IS R AS DEFINED ABOVE, AND Y IS SALT-FORMING ANION, WHICH ONIUM SALTS ARE WEAKLY ACIDIC TO WEAKLY BASIC, THEIR WATER SOLUTIONS HAVING A PH BETWEEN 5 AND 10, SAID CATHOLYTE CONTAINING A CURRENT-CARRIER IN AN AMOUNT SUFFICIENT TO PROVIDE A CONDUCTIVITY OF AT LEAST 0.0005 OHM-1 CM.-1, SAID CURRENT-CARRIER BEING A DISSOLVED CURRENT-CARRYING SALT WHICH, IN WATER, HAS A PH IN THE RANGE OF 5 TO 10; AND RECOVERING AN ORGANOMETAL COMPOUND FROM SAID SOLUTION. 